Phytanic acid

A branched-chain fatty acid derived from phytol

Phytanic acid
Phytanic acid.svg
Identifiers
CAS Number
PubChem CID	5280447
ChemSpider ID
UNII
ChEBI	28802
ChEMBL
Properties
Chemical Formula
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Appearance
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Boiling Point
Hazards
GHS Pictograms	[[File:|50px]]
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NFPA 704	[[File:|50px]]
References

Phytanic acid is a branched-chain fatty acid that is derived from phytol, a component of chlorophyll. It is a saturated fatty acid with the chemical formula C₂₀H₄₀O₂. Phytanic acid is notable for its role in human metabolism and its association with certain metabolic disorders.

Biochemistry

Phytanic acid is not synthesized by the human body but is obtained through the diet, primarily from the consumption of ruminant animal fats, dairy products, and certain fish. It is absorbed in the intestine and transported in the blood as part of chylomicrons.

In the human body, phytanic acid undergoes alpha-oxidation in the peroxisomes, a process that is necessary because its branched structure prevents it from undergoing beta-oxidation directly. The enzyme phytanoyl-CoA hydroxylase catalyzes the first step of alpha-oxidation, converting phytanic acid to pristanic acid, which can then enter the beta-oxidation pathway.

Clinical significance

Phytanic acid accumulation in the body is associated with Refsum disease, a rare genetic disorder caused by mutations in the PHYH gene, which encodes the enzyme phytanoyl-CoA hydroxylase. This leads to impaired alpha-oxidation of phytanic acid, resulting in its accumulation in tissues and plasma.

Symptoms of Refsum disease include peripheral neuropathy, retinitis pigmentosa, anosmia, and cerebellar ataxia. Management of the disease involves dietary restriction of phytanic acid by avoiding foods rich in this fatty acid.

Metabolic Pathway

The metabolic pathway of phytanic acid involves several steps:

1. Dietary intake: Phytanic acid is ingested through foods such as dairy products, beef, lamb, and certain fish.
2. Absorption and transport: It is absorbed in the intestine and transported in the bloodstream as part of chylomicrons.
3. Alpha-oxidation: In the peroxisomes, phytanic acid undergoes alpha-oxidation, starting with the action of phytanoyl-CoA hydroxylase, converting it to pristanic acid.
4. Beta-oxidation: Pristanic acid is further broken down via beta-oxidation in the mitochondria to produce energy.

Research and Future Directions

Research into phytanic acid continues to explore its role in human health and disease. Studies are investigating its potential involvement in other metabolic disorders and its broader impact on metabolic health.

Also see

• Refsum disease
• Fatty acid metabolism
• Peroxisome
• Chlorophyll